STEES : MOLLTJSCA OF THE PORCTTPINE EXPEDITION. 31 



EETUSA, Brown. 



The name Retusa Wcas proposed by Brown in the scarce first edition 

 of his 111. Conch. Gt. Brit., published in 1827, for Bulla ohtusa, 

 Mont., and two new species, j»/<"c«^« and discors; he gave no diagnosis, 

 but the forms were figured. In the first edition of his "Conchologist's 

 Textbook " the only example is R. plicata. 8ave for the protoconch, 

 which may or may not be a generic character, this appears to agree 

 with Tornatma, Adams. 



Retusa excavata (Jeffreys). PL III, Figs. 7, la. 



Utrictilus excavatus, Jeffreys: Rep. Brit. Assoc, 1880 (1881), p. 387 

 [nom. nud.]; Pilsbry, Man. Conch., vol. xv, p. 214. 



"Porcupine" Expedition, 1870, Stations 9, 14, 17. 



Bistribution. — Bay of Biscay (Jeffreys). Pliocene of Ficarazzi 

 (Jeffreys). 



1 propose to fix a ' type ' from amongst the specimens in the 

 British Museum of this .species, and from an examination of it the 

 following notes are compiled. Shell forming an oblong cylinder, 

 slightly inflated in the middle, opaque and fairly glossy, marked by 

 slight lines of growth; spire almost flat, the whorls being angular and 

 shouldered at the top, and separated by a deep suture; the apical 

 whorl is large, shining, and globular; mouth narrow above and 

 expanded below, not reaching to the top of the whorl ; inner lip 

 fairly well marked and continuous with the outer lip above, i-eflected 

 over the pillar, leaving a slight indication of an umbilical chink. 

 Alt. 2'5, diam. max. 1*2 mm. 



Retusa lactea (Jeffreys). PL III, Fig. 4. 



Zrtriculm lacteus, Jeffreys: Ann. Nat. Hist., ser. iv, vol. xix, p. 334. 

 Retusa lactea, Jeffreys: Pilsbry, Man. Conch., vol. xv, p. 213. 



"Porcupine" Expedition, 1869, Station 20. 



Dislrihution. — "Valorous" Expedition, Station 12, 1450 fathoms. 



The specimen figured is that from the "Porcupine" Expedition 

 referred to by Jeffreys ; it is, as he states, broken. 



Retusa mamillata (Phil.). 



Bulla mamillata, Philippi : Enum. Moll. SiciL, vol. i, p. 122. pi. vii, 



fig. 20. 

 Retusa maoiillata, Philippi : Pilsbry, Man. Conch., vol. xv, p. 206. 



"Porcupine" Expedition, 1870, Station 50; Yigo Bay; Adventure 

 Bank, 92 fathoms. 



Bistn'hufion. — Atlantic from Norway to the Canaries ; Mediterranean 

 and Adriatic Seas (Pilsbry). Miocene and Pliocene of Europe. 



Retusa Marshall!, n.sp. PL III, Figs. 5, 6, 6a, 6b. 



Shell ovate, white, thin, smooth save for very fine lines of growth. 

 Protoconch large, sinistral, and set at an angle to the shell. Spire 

 flat, being slightly concave, with a deej), channelled suture. Whorls 4. 



